Posted
by
samzenpus
on Thursday April 05, 2012 @10:56PM
from the healthy-light dept.

cylonlover writes "An international team of scientists has created a handheld, battery powered device that has been shown to effectively rid skin of bacteria in an instant by blasting it with plasma. The plasma flashlight, which shouldn't be confused with a plasma torch that will damage much more than bacteria if used on the skin, could provide a convenient way for paramedics and military personnel to deal with harmful bacteria in the field. The self-contained device is powered by a 12 V battery and doesn't require any external gas feed or handling system. The plume of plasma it generates is between 20-23C (68-73.4F), so it won't damage the skin. It is also fitted with resistors to stop it heating up and becoming too hot to touch. Its creators say it can also be easily manufactured at a cost of less than US$100 per unit."

I like the bacteria that live on my body.. we have a relationship, once in a while a renegade causes some mayhem but otherwise its a very healthy existance that we've agreed to. Keep your death lights away, I dont need them.

I like the bacteria that live on my body.. we have a relationship, once in a while a renegade causes some mayhem but otherwise its a very healthy existance that we've agreed to. Keep your death lights away, I dont need them.

You take for granted the skin that acts as a physical barrier between the microbes that live on your body. For injuries such as severe burns and auto accidents involving road rash victims are not so lucky. This device sounds like an amazingly suitable solution that provides minimal interferance/physical contact. Although in this context, the irony of using a plasma to disinfect such wounds is not lost.

I like the bacteria that lives on my body too... not so much the bacteria in the creek on the side of the road seeping into my open wounds thanks to the asshat who just cut me off.

This kind of thing could be great for people who have allergies to anti-bacterial agents or, as the summary states, "provide a convenient way for paramedics and military personnel to deal with harmful bacteria in the field." If you're going to complain about killing off the good bacteria on your skin then rail about anti-bacterial soap and hand sanitizer, their daily use does far more damage to the good bacteria on your skin than any $100+ device used in an emergency will ever do.

I've never heard of anyone being allergic to an anti-bacterial agent. I've heard of latex allergies (from gloves) and allergies to some *perfumes* that are *added* to dissinfectants, but none regarding dissinfectants themselves. I do quite a bit of first aid stuff, so if you have any links to a source where I could find out if this is true (and specifically which chemicals are an issue), please post them.

Based on nearly every emergency room doctor asking me if I have an allergy to Penicillin [wikipedia.org] during the medical history part of the interview I figured it was an actual real thing. Still, just in case, I found this Wiki page talking about Penicillin drug reactions [wikipedia.org] that covers allergic reactions and has links to some studies or some such thing.

Honestly I'm not really well versed in the nitty gritty medical terms so I didn't entirely understand everything on the page, but I figure if its important enough for a d

Antibacterials like simple alcohols or hydrogen peroxide are small molecules, and small molecules can't generate an immune response directly. However, small molecules can act as haptens: They bind to some protein and the combination generates such a response. Urushiol is the best example of a hapten - it's the "active ingredient" in poison ivy, oak, and sumac.

That said, I've never heard of an allergic reaction to either a simple alcohol or hydrogen peroxide. Skin irritation, sure, but not an allergic reaction.

Iodine is another matter. Antibacterial iodine is usually povidone-iodine, and it definitely is possible to have a severe allergic reaction to it. Various sources disagree as to why this happens, but it definitely does.

It's also possible, although rare, to have an allergic reaction to iodine-based contrast dyes. My mother nearly died from an injection some of this stuff, as a matter of fact.

I've definitely heard of the iodine issues, but is that the iodine itself, or the stuff they add *to* it to make it do other fun stuff (like the dyes, etc)? As for Penicillin, that is not the kind of thing I was talking about (as WCLPeter so graciously explained).

That's really the question, isn't it? Depending on what you read, you'll find people claiming that it's impossible to have an allergy to iodine itself and others claiming that it is. People have severe allergies to seafood, to iodine-based contrast material, and to povidone-iodine. But others point out that being allergic to one doesn't mean you're allergic to the others - there's some correlation, but it's small. And all of them contain other stuff.

It's not just "the common use" either - I have a scientist friend who has a latex allergy (daily exposure to lab gloves led to the development a few years after she finished her doctorate) who went into anaphylactic shock on two separate occasions - once (right after she found out) while blowing up balloons at her niece's birthday party, and once after eating food prepared by people wearing latex gloves (there was nothing indicating that the people prepping the food were wearing gloves).

I'm allergic to sulphur based anti-biotics and topical application of a variety of sulphur compaunds commonly used anti-bacterial products. Anecdotally, my doctor tells me it's not uncommon, mostly causing mild skin irritation, but that my case is particularly severe. Beyond that I can't state a source...

you're going to complain about killing off the good bacteria on your skin then rail about anti-bacterial soap and hand sanitizer, their daily use does far more damage to the good bacteria on your skin than any $100+ device used in an emergency will ever do

Personally, i don't use either, as they are bad.

However, i do agree, in cases where your skin is open, you do want to stop bad bacteria from entering and its an acceptable risk to burn off some good in order to stop the bad. ( be it a simple paper cut, sever cat scratch or being run over by a truck and your arm is danging..)

With the prevalence of MSRA I've wondered why portable/handheld ozone generators have not become prevalent for hospital/clinical use. If this system is as effective it would eliminate the need for liquid suspension of ozone to prevent inhalation hazards. In fact, I wonder how long before other industries requiring sanitation abandon ozone systems in favor this plasma light system.

MRSA is a direct product of our total war on all bacteria. Most people who become infected with MRSA were exposed to it in a hospital. Hospitals have basically become ultra-efficient incubators for MRSA.

MRSA is no the product of a total war on bacteria, but the product of a careless war.

Our use of antibiotics is like sending a single policeman with a single gun to every incident reporting and not caring if they return. In most cases it will be enough, but in the long run there will be many criminals with police guns in their hands(and even if they do not need the new guns, they still get fresh ammo all the time).

Hospitals are then favelas handled like that, i.e. sending one or two policemen with automatic

This used to be the case, but not anymore. Hospitals were (and still are) a breeding ground for resistant bacteria, MRSA included. These MRSA bacteria caused invasive infections (like pneumonia and bacteremia) that were very hard to treat and lead to many patient deaths. CA-MRSA (community-acquired MRSA) is a relatively new development over the last 10 years or so, and as the name implies, are typically contracted in the community. These bacteria are thankfully less invasive, but tend to cause a lot of

I don't think bacteria are not going to become resistant to these plasma "flashlights" any more than they are going to become resistant to alcohol, lysol, or autoclaves. They wouldn't be bacteria any more.

An international team of scientists has created a handheld, battery powered device that has been shown to effectively rid skin of bacteria in an instant by blasting it with plasma. The plasma flashlight, which shouldn’t be confused with a plasma torch that will damage much more than bacteria if used on the skin, could provide a convenient way for paramedics and military personnel to deal with harmful bacteria in the field.

The self-contained device is powered by a 12 V battery and doesn’t require any external gas feed or handling system. The plume of plasma it generates is between 20-23C (68-73.4F), so it won’t damage the skin. It is also fitted with resistors to stop it heating up and becoming too hot to touch. Its creators say it can also be easily manufactured at a cost of less than US$100 per unit.

In an experiment carried out by the scientists, the plasma flashlight effectively inactivated thick biofilms of Enterococcus faecalis, a bacterium that often infects the root canals in dental treatments and is highly antibiotic- and heat-resistant. Created by incubating the bacteria for seven days, the biofilms consisted of 17 different layers of bacteria. After treating each biofilm with the plasma flashlight for five minutes, the plasma was found to penetrate deep into the very bottom layer and inactivate the bacteria.

“In this study we chose an extreme example to demonstrate that the plasma flashlight can be very effective even at room temperature,” said co-author of the study, Professor Kostya (Ken) Ostrikov, from the Plasma Nanoscience Centre Australia, CSIRO Materials Science and Engineering. “For individual bacteria, the inactivation time could be just tens of seconds.”

While plasma has previously been shown to effectively kill bacteria and viruses on the surface of the skin and water, the exact mechanism behind this is still not understood. Ultraviolet radiation has been theorized as a reason, but the jet created by the plasma flashlight is low in UV radiation, which adds to the safety of using the device on a person’s skin. The reactions between the plasma and the surrounding air has also been suggested as another possibility.

The international team behind the plasma flashlight consists of scientists from Huazhong University of Science and Technology, CSIRO Materials Science and Engineering, The University of Sydney and the City University of Hong Kong. Their work is detailed in the Journal of Physics D: Applied Physics.

"It is also fitted with resistors to stop it heating up and becoming too hot to touch."

Um. What? Whoever wrote this clearly has no electronics knowledge. This is Slashdot. We have real engineers and scientists around here. Could we have real science reporting, please? Not only is that sentence moronic, the entire article fails to explain how this device operates, even in the most basic terms. It's shaped like a flashlight, but that seems to be where the similarity ends. It is not a light source whatsoever. From the actual scientific publication, it appears that this is a high voltage pulse generator that produces a discharge between the device and the patient. A series of 100ns pulses at 20KHz repetition rate ionizes the air between the device and the patient, thus producing the ions that kill the bacteria. The peak current is 6mA, but the average current (and thus average power) is very low so heating is minimal. This is a relatively low-tech device electronically, and could easily be replicated by many hobbyists.

Yes, but that doesn't necessarily mean the total heat dissipated increases. If you have a constant voltage supply (typical), adding a resistor in *series* with the load *reduces* the total power dissipated. Yes, the resistor generates heat, but that is more than offset by a reduction in the heat generated by the load.

If a resistor in series with the load reduces the current by 1/2, the power dissipated by the load is reduced to 1/4 what it would be without the load.

Constant voltage is the most common case, as it is supplied by outlets and batteries, but some power supplies provide constant current, in which case adding a resistor in series would not alter the load power dissipation, and (as you are asserting) the heat generated by the resistor would add to the net heat dissipation.

Supposing you're driving an LED (disclaimer, I am not an LED lighting engineer), you'd want to keep it in the correct current range, so you'd use a constant current power supply. If you put a second identical LED in series with the first, you'd double the load resistance [note 1], but the power supply's voltage would adjust so the current remains the same. The Captain Obvious result is that if you drive 2 serially connected LEDs off your constant current supply instead of 1, the power dissipated doubles. The somewhat less obvious result is that if you're using a constant voltage supply the total power dissipated drops, so the the power dissipated by each of the two LEDs is less than one half what a single LED would.

note 1: LEDs aren't linear in their response like a plain resistor, so this wouldn't necessarily be true if we were talking about a constant voltage supply like a battery.

The article is http://iopscience.iop.org/0022-3727/45/16/165205/pdf/0022-3727_45_16_165205.pdf (may need registering, but it's free to download for a month)

The summary is semi-correct, but phrased terribly. The resistors provide enough ballast to limit the output power to 60mW. If you short the device the combined 100MegOhm is only going to dissipate a Watt of power. It's not so much to stop the device being warm to the touch, it's to stop the device from blowing up and/or burning your patient.

If they weren't there then you're essentially trying to dump 10kV into a human body which is roughly 10kOhm to be conservative. The resistance of air is about a megaOhm per centimetre, but presumably if it's arcing due to the plasma it'll have negligible resistance after ionisation. What would probably happen is the DC converter would blow up, but you'd get a pretty nasty shock.

Similarly as the human body has a maximum resistance of a few hundred kOhm, the plasma current is dominated by the two ballast resistors. Incidentally, it looks like the patient will either need to be wired up or will have to disinfect themselves because the thing works by pulling your body to ground with respect to the electrodes.

This thing generates plasma -- from what? Probably the air. So my guess is that it applies a pulse of high voltage to ionize the air, producing a plasma. Now suppose the plasma is too hot, what would adding a resistor in series do?

I don't know, but this sounds more like a lightsaber. Just crank up the power a little bit.

Actually that is precise how the laser flashlights in Larry Niven's Ringworld (1970) operated. On a low setting they were pretty much flashlights. They were designed to be covert, non-obvious weapons. However if the power was dialed up you had a powerful energy weapon for slicing things at a distance.

In my Universe[1], I would let you slide on the muffler bearings, BUT the bacon stretcher is just taking things too far!Repent your evil ways and use a bacon condenser instead.Just think, put in 10 kilos of bacon, and get a handful of bullion cube sized bacon bites!Density FTW! (just ask my bathroom scales!);-)

All hyperbolic humour/sarcasm aside......a 'bacon stretcher'?That's a new one for me, first time I've encountered that one...Thanks!:-)

You never worked at a restaurant? Maybe it's just breakfast restaurants. Between looking for the non-existent attic/basement for a non-existent bacon stretcher and figuring out how not to tap the grease trap in the parking lot(big mess), it's amazing I passed my 1st week dish dogging. Luckily I did, good times were had... If my parents only knew.

Wonder if it works on solid surfaces as well. Just imagine, use it on your face a few times a day and eliminate acne. Of course you'll probably get really tan really quickly, but yeah. No more Yellowish Brown splotches as you leave after donating blood, they can sanitize you with a quick brush of a plasma flashlight. If places replaced the costly paper towel dispensers and soap dispensers with one of these, (a heavy duty plugin version) you could sanitize the hands of a hundred people in like a minute! No more soap and wasteful paper towels that are almost never recycled after use as a hand towel. No more costly hot air hand dryers that take hundreds of watts to run.

Notice I didn't say that the sinks would be removed. You would have plenty of opportunity to rinse off, then use the plasma flashlight or whatever clever patented name they create for it and then dry off somehow. The material in question would be removed, and any remaining bacteria dead, but maybe they should make you drip dry your hands as a penalty for being clumsy and getting material on your hands.

Something fishy about this. "Fitted with resistors to stop it heating up". Is that a joke? As I remember, resistors are about turning unwanted current flow into heat.
Also - from the article, the way I interpret it, it seems it takes tens of seconds of exposure to kill the bacteria.

Hey, when shopping for a house in Santa Fe, I paid a few hundred bucks to a very professional Assessment for Microbial Contamination from Dan Stih of www.HealthyLivingSpaces.com. It included counts of a variety of classes/species of fungus hanging out outside and contrasted that with the air quality in various parts of the house. It then honed in on physical penetration tests of surfaces like wood, tile grout and drywall, with an detailed recommendation for a remediation protocol.I was very satisfied with

I wonder if the bacteria that live on my skin stop more germs than my immune system. I suspect so since they have the numbers. It is sad that I can't find a bar of soap that does not have anti bacterial stuff in it. Germophobes have come down with some nasty fungal infections after ridding their skin of bacteria. It sounds useful for treating that missing patch of skin that time I left it on the goose poop decorated bike path. That one started to show sign of blood poisoning.

I don't recall specifically any info on skin bacteria, but many species of bacteria use chemical warfare to combat rivals and competition.

In addition, mostly they seem to rely on the 'crowding out the competition' tactic that weeds use on grass and gardens...'consume all the resources to deny your enemy a foothold'.It's a proven and valid strategy for most species of all orders(not just bacteria), historically.

Trivial/arcane fact:40%-65% of the volume of 'the average human turd' is dead bacterial corpses fr

While plasma has previously been shown to effectively kill bacteria and viruses on the surface of the skin and water, the exact mechanism behind this is still not understood

Hmmm thanks, but I'd prefer to sit tight until we know exactly how it does this. I know it has probably gone through rigourous testing etc., but if we've no idea how it works we've no idea how it could be causing other damage. We used to think throwing antibiotics at every possible problem was a great idea until we discovered transmiss

Yes, and it worries me to read "we don't know how it kills the bacteria" and "it's only 20-23C, so it won't damage the skin" in the same article. I'm not one of those "OMG it might cause cancer" types, but this seems to be one example where such fears could be warranted. After all, you could say "it's only 20-23C so it won't kill any bacteria" but that's obviously not true. Could we maybe first figure out what it does exactly before declaring it safe and letting paramedics use it on a daily basis?

The thing produces free radicals, which are molecules with unpaired electrons. Since electron really prefer to be paired, a free radical will catch an electron from any nearby molecule, turning the later into another free radical. Each time a molecule from a cell is touched by this chain reactions, it is damaged and will need repair. This is true for microbes, but for human cells as well

Cells have defenses. Molecules such as Vitamin C and E, Glutathione, or the SuperOxyde Dismutase enzyme, will be able to e

Ozone and free radicals – very bad for bacteria. Further, this is not plasma, this is corona. Plasma is fully ionised gas. Corona on the other hand is an area or volume of week discharge through a gas – which is what this is. So this is a pen shaped thing with a week high frequency ~20kV discharge, almost certainly capacitivly coupled to the output to limit current. If it isn’t capacitivly coupled or otherwise current limited – hello RF burns!

You evilutionists can't fool me! Everyone knows diseases and infections aren't caused by "invisible tiny creatures", but by demons! You are just trying to fool everyone into buying your useless devices so you can raise more money to promote your atheist-satanic-Muslim agenda! Admit it! [/tongueincheek]